A link in their pasts leads an honest cop to a fugitive gang boss, whose cryptic warning spurs the officer on a quest to save Mumbai from cataclysm. Sartaj Singh is a troubled police inspector in Mumbai police, living on sleeping pills and seeking validation from a police force he nevertheless loathes for its corruption. He receives an anonymous phone call from Ganesh Gaitonde, a notorious crime lord who has been missing for 16 years. He tells Singh to save the city in 25 days, which initiates a chain of events that burrows deep into India’s dark underworld. In the journey, Singh is helped by a Research and Analysis Wing officer, Anjali Mathur.